A Small LF Loop Antenna

Total Page:16

File Type:pdf, Size:1020Kb

A Small LF Loop Antenna A small LF loop antenna Klaus Betke This paper describes a loop antenna for receiving purposes in the frequency range 10 kHz to 150 kHz; with reduced performance it can be used up to 600 kHz. The antenna is mainly intended for quick direction finding of unidentified utility radio stations. The prototype was built for indoor use. This is possible because it picks up much less noise from the mains than wire antennas, which are most often useless indoors, in particular at frequencies below 50 kHz. Design considerations Receiving antennas can be characterised by their “effective height” heff. The output voltage U for an electrical field strength E is then given by U = heff $ E The effective height of a loop antenna is 2onAcos w h = , eff k where n is the number of turns, A is the loop area, l is the wavelength, and j is the angle between loop plane and transmitter. As we see, the loop’s output voltage is inverse proportional to l, or proportional to the frequency f. Actually the loop senses the magnetic field, not the electrical field. But in the far field of a transmitting antenna (a condition that is usually met), electric and magnetic field vector are simply related by a factor. This is the reason why the output voltage can be expressed in terms of the electrical field strength E. At 30 kHz, the effective height of a single turn loop of 1 m diameter is only 0.5 mm. This is very small compared to an E-field antenna of similar size: The theoretical value for a 1 m vertical rod over a conducting surface is heff = 0.5 m. So why not increase the number of turns to, say, 1000? Unfortunately the more turns, the larger the inductance L and hence the larger the inductive reactance X = 2ofL in series with the “generator “voltage U. In multi-turn loops, L increases by a factor of about n1.8. Furthermore, the inductance and the loop’s stray capacitance form a resonant circuit, which may limit the usable frequency range. On the other hand, if the loop is connected to an amplifier with a very low input impedance, the inductance can be used to compensate for the U ~ f property. Please refer to [1] for a thorough discussion of this approach. If the amplifier’s input resistance is less than the inductive reactance at the lowest frequency of interest, the output voltage is independent of frequency. The low resistance also damps the stray parallel resonance to Q << 1. Due to the (almost) shortened loop inductance, this kind of antenna is completely insensitive to the E-field. The loop shown in figure 1 has an inductance of 1.2 mH; its resonance frequency is about 350 kHz. At 10 kHz, the reactance is 75 ohms. With an amplifier input resistance – 2 – between 30 and 100 ohms, however, the sensitivity was found to be insufficient for frequencies above 70 kHz, compared to my other active antennas, a Rohde & Schwarz HE-011, and a Wellbrook ALA1530 loop. For this reason, a slightly different design was chosen: Instead of using a “zero input impedance” amplifier, the loop is terminated by a load of a few kohms (the observed gain lack was not caused by the amplifier; the circuit used in the first tests had a flat frequency response up to well beyond 500 kHz). Figure 1. The prototype loop has 40 turns and a diameter of 38 cm. Circuit description There is nothing special with the amplifier shown in figure 2. With the load resistance R1 = 2.2 kW, the Q factor of the loop’s inherent parallel resonance still fairly below 1, hence the resonance does not cause problems. The feedback circuit of R5, R6 and C3 makes the signal loss at low frequencies less severe. Since the antenna was intended for radio monitoring rather than for precise measurements, no further effort was taken to obtain a flat frequency response. Resistor R7 in series with the amplifier output ensures stability when using a long cable. The circuit is powered remotely through the antenna cable. The splitter made of L1 and C7 can be used, but other power supplies for active antennas might do as well. I use the 24 V supply for the R&S HE-011. A clean supply voltage is mandatory. Switching regulators (e.g. tapping the PC power supply) will usually cause problems, but linear power supplies can also be noisy. Integrated regulators like the LM317 or the 78xx series need a large capacitor of 1000 µF or more at the input terminal to reduce the noise in the LF and VLF range, in parallel to the common 100 nF. – 3 – Figure 2. Circuit diagram of the loop amplifier Construction As can be seen from the quick-and-dirty prototype in figure 1, the construction can be kept very simple. The loop has a diameter of about 40 cm and 40 turns, which needed a little less than 50 metres of wire. Neither the diameter, nor the number of turns nor the exact shape are critical. The loop is easier to wind on some kind of bobbin, a box for example. You can bend the antenna into a circular shape afterwards. I used 1.5 mm² “electrician’s wire” (diameter including insulation 2.7 mm, core diameter 1.4 mm). Thinner wire is ok; with a 0.5 mm wire, the inductance will increase by less than 20 percent and the resistance still does not matter. With thick wire, however, the antenna can be built without a supporting structure; the loop in fig. 1 is held together simply by cable binders. The amplifier was built in a conventional technique (with old-fashioned components that still have wires…) on a small piece of strip-line material (figure 3). An OP27 was chosen for U1 “because it was there”. Other types like LT1028, or so-called audio op-amps like LM833 (a dual op-amp) will probably also work. Anyhow, everything said here should be taken as ideas for own experiments rather than as a bullet-proof recipe; the whole thing can still be optimised. Figure 3. The amplifier circuit – 4 – Practical experiences The results with this antenna of course strongly depend on the local noise floor. While writing this, I can hear Alpha navaid stations [2] Krasnodar and Novosibirsk on 14.88 kHz, with the loop two arm lengths away from the computer. When the PC is off, the beeps are audible on the other two Alpha frequencies 11.9 and 12.65 kHz as well. Below about 250 kHz, the antenna has very sharp bearing minima. You can at least distinguish whether a station is located in direction NW or in NNW (or in the opposite directions of course, as bearings with loops are ambiguous). A precise direction calibration down to the one degree level is pointless, not only due to the semi-rigid construction, but also due to the portable character of the antenna, since the deviation strongly depends on the environment. As a consequence of the non-zero termination resistance, the loop is a bit sensitive to electrical field components and to capacitive coupling at higher frequencies, and above 250 kHz, the antenna slightly “squints”. That is, bearing is still possible, but the angle between the two minima is not exactly 180°, and the antenna should be rotated without grasping the loop itself. Below about 100 kHz, however, the loop is completely insensitive to touching. References [1] Marco Bruno, IK0ODO: Thinking about Ideal Loops. February 2001. Available at www.vlf.it. [2] Trond Jacobsen: The Russian VLF Navaid System Alpha, RSDN-20. July 2000. Available at www.vlf.it. July 2001 – Minor corrections October 2003.
Recommended publications
  • High Frequency Communications – an Introductory Overview
    High Frequency Communications – An Introductory Overview - Who, What, and Why? 13 August, 2012 Abstract: Over the past 60+ years the use and interest in the High Frequency (HF -> covers 1.8 – 30 MHz) band as a means to provide reliable global communications has come and gone based on the wide availability of the Internet, SATCOM communications, as well as various physical factors that impact HF propagation. As such, many people have forgotten that the HF band can be used to support point to point or even networked connectivity over 10’s to 1000’s of miles using a minimal set of infrastructure. This presentation provides a brief overview of HF, HF Communications, introduces its primary capabilities and potential applications, discusses tools which can be used to predict HF system performance, discusses key challenges when implementing HF systems, introduces Automatic Link Establishment (ALE) as a means of automating many HF systems, and lastly, where HF standards and capabilities are headed. Course Level: Entry Level with some medium complexity topics Agenda • HF Communications – Quick Summary • How does HF Propagation work? • HF - Who uses it? • HF Comms Standards – ALE and Others • HF Equipment - Who Makes it? • HF Comms System Design Considerations – General HF Radio System Block Diagram – HF Noise and Link Budgets – HF Propagation Prediction Tools – HF Antennas • Communications and Other Problems with HF Solutions • Summary and Conclusion • I‟d like to learn more = “Critical Point” 15-Aug-12 I Love HF, just about On the other hand… anybody can operate it! ? ? ? ? 15-Aug-12 HF Communications – Quick pretest • How does HF Communications work? a.
    [Show full text]
  • An Electrically Small Multi-Port Loop Antenna for Direction of Arrival Estimation
    c 2014 Robert A. Scott AN ELECTRICALLY SMALL MULTI-PORT LOOP ANTENNA FOR DIRECTION OF ARRIVAL ESTIMATION BY ROBERT A. SCOTT THESIS Submitted in partial fulfillment of the requirements for the degree of Master of Science in Electrical and Computer Engineering in the Graduate College of the University of Illinois at Urbana-Champaign, 2014 Urbana, Illinois Adviser: Professor Jennifer T. Bernhard ABSTRACT Direction of arrival (DoA) estimation or direction finding (DF) requires mul- tiple sensors to determine the direction from which an incoming signal orig- inates. These antennas are often loops or dipoles oriented in a manner such as to obtain as much information about the incoming signal as possible. For direction finding at frequencies with larger wavelengths, the size of the array can become quite large. In order to reduce the size of the array, electri- cally small elements may be used. Furthermore, a reduction in the number of necessary elements can help to accomplish the goal of miniaturization. The proposed antenna uses both of these methods, a reduction in size and a reduction in the necessary number of elements. A multi-port loop antenna is capable of operating in two distinct, orthogo- nal modes { a loop mode and a dipole mode. The mode in which the antenna operates depends on the phase of the signal at each port. Because each el- ement effectively serves as two distinct sensors, the number of elements in an DoA array is reduced by a factor of two. This thesis demonstrates that an array of these antennas accomplishes azimuthal DoA estimation with 18 degree maximum error and an average error of 4.3 degrees.
    [Show full text]
  • The 3-D Folded Loop Antenna
    The 33---DD Folded Loop Antenna Dave Cuthbert WX7G Introduction This article will introduce you to an antenna I call the 3-Dimensional Folded Loop. This antenna is the result of my continuing efforts to compact full-size antennas by folding and bending the elements. I will first describe the basic 3-DFL and then provide construction details for the 2-meter and 10-meter 3-DFL antennas. Here are some features of the 3-DFL: • Reduced height and footprint • Full-sized antenna performance • Wide bandwidth • Ground independent • Can be built using standard hardware store parts Description The 3-D Folded Loop, or simply the 3-DFL, is a one-wavelength loop that is reduced in height and width by being folded into three dimensions. A 28-MHz loop that is normally 9 feet on a side becomes a box-shaped antenna that is 3 by 3 by 5 feet. It exhibits performance that is competitive with a ground plane yet requires only 15 square feet of ground area versus 50 for the ground plane. So, compared to a ground plane it is only 60% as tall and has a footprint only 30% as large. And the 2-meter 3-DFL is so compact it can be placed on a table and connected to your HT for added range and reduced RF at the operating position. 1 3-DFL Theory of Operation The familiar one-wavelength square loop is shown in Fig. 1 and is fed in the center of one vertical wire. Note that the current in the vertical wires is high while the current in the horizontal wires and is low.
    [Show full text]
  • A Flexible 2.45 Ghz Rectenna Using Electrically Small Loop Antenna
    A Flexible 2.45 GHz Rectenna Using Electrically Small Loop Antenna Khaled Aljaloud1,2, Kin-Fai Tong1 1Electronic and Electrical Engineering Department, University College London, London, UK, [email protected] 2Electrical Engineering Department, King Saud University, Riyadh, Saudi Arabia Abstract—We present the concept and design of a compact schlocky diode connected in series to one of the two feed flexible electromagnetic energy-harvesting system using electri- terminals of the antenna and to the coplanar transmission line, cally small loop antenna. In order to make the integration of the a capacitor to minimize the ripple level. The reported system system with other devices simpler, it is designed as an integrated system in such a way that the collector element and the rectifier in this letter is sufficiently capable of reusing low microwave circuit are mounted on the same side of the substrate. The energy for both flat and curved configurations. rectenna is designed and fabricated on flexible substrate, and its performance is verified through measurement for both flat and curved configurations. The DC output power and the efficiency II. DESIGN AND RESULT are investigated with respect to power density and frequency. It is observed through measurements that the proposed system The two main parts of rectenna system are largely designed can achieve 72% conversion efficiency for low input power level, individually and unified through the matching network. In this -11 dBm (corresponding power density 0.2 W=m2), while at the work, the proposed rectenna is built as an integral system, and same time occupying a smaller footprint area compared to the thus the rectifier circuit is matched to the collector to maximize existing work.
    [Show full text]
  • The Classic Rain-Gutter Loop Antenna – Is It Any Good?
    The Classic Rain-Gutter Loop Antenna – Is it any Good? A simple technical look at an HF horizontal loop of wire strung around your house at rain-gutter height, plus. some novel loop disguise techniques. By John Portune W6NBC Compromise disguise antennas are no strangers to hams, especially on HF. But which ones are worth the effort? We often just put them up and hope for the best. But when I moved to a CC&R restrictive mobile home park recently, I wanted better answers, particularly for the classic rain-gutter loop, Figure 1. I couldn’t put up more of an HF antenna without the neighbors noticing. But was it any good, or only little more than a dummy load? Figure 1: Classic rain-gutter-height loop, elevated on standoffs (stylized for emphasis) To find out, I challenged the rain-gutter loop with EZNEC antenna modeling software. This required best-case and worst-caswe models to encompass most house variables: (1) two loop heights, (2) two house types and (3) several bands. These would place most houses somewhere within these limits. Loop heights were: 10 ft. (rain-gutter height) and 25 ft. (a more conventional loop height). House types were: all wood (best case) and stucco/chicken wire (worst case). Bands were: 40M, 20M and 10M. Why didn’t I include 80M and 160M? Well, I did at first, but right up front, EZNEC revealed something very important about horizontal loops – Rule of Thumb 1. RULE OF THUMB 1 To be efficient, a closed loop must have a perimeter greater than one wavelength (1λ) on the lowest band in use.
    [Show full text]
  • 3.1Loop Antennas All Antennas Used Radiating Elements That Were Linear Conductors
    SECX1029 ANTENNAS AND WAVE PROPAGATION UNIT III SPECIAL PURPOSE ANTENNAS PREPARED BY: MS.L.MAGTHELIN THERASE 3.1Loop Antennas All antennas used radiating elements that were linear conductors. It is also possible to make antennas from conductors formed into closed loops. Thereare two broad categories of loop antennas: 1. Small loops which contain no morethan 0.086λ wavelength,s of wire 2. Large loops, which contain approximately 1 wavelength of wire. Loop antennas have the same desirable characteristics as dipoles and monopoles in that they areinexpensive and simple to construct. Loop antennas come in a variety of shapes (circular,rectangular, elliptical, etc.) but the fundamental characteristics of the loop antenna radiationpattern (far field) are largely independent of the loop shape.Just as the electrical length of the dipoles and monopoles effect the efficiency of these antennas,the electrical size of the loop (circumference) determines the efficiency of the loop antenna.Loop antennas are usually classified as either electrically small or electrically large based on thecircumference of the loop. electrically small loop = circumference λ/10 electrically large loop - circumference λ The electrically small loop antenna is the dual antenna to the electrically short dipole antenna. That is, the far-field electric field of a small loop antenna isidentical to the far-field magnetic Page 1 of 17 SECX1029 ANTENNAS AND WAVE PROPAGATION UNIT III SPECIAL PURPOSE ANTENNAS PREPARED BY: MS.L.MAGTHELIN THERASE field of the short dipole antenna and the far-field magneticfield of a small loop antenna is identical to the far-field electric field of the short dipole antenna.
    [Show full text]
  • Broadband Antenna 1
    Broadband Antenna Broadband Antenna Chapter 4 1 Broadband Antenna Learning Outcome • At the end of this chapter student should able to: – To design and evaluate various antenna to meet application requirements for • Loops antenna • Helix antenna • Yagi Uda antenna 2 Broadband Antenna What is broadband antenna? • The advent of broadband system in wireless communication area has demanded the design of antennas that must operate effectively over a wide range of frequencies. • An antenna with wide bandwidth is referred to as a broadband antenna. • But the question is, wide bandwidth mean how much bandwidth? The term "broadband" is a relative measure of bandwidth and varies with the circumstances. 3 Broadband Antenna Bandwidth Bandwidth is computed in two ways: • (1) (4.1) where fu and fl are the upper and lower frequencies of operation for which satisfactory performance is obtained. fc is the center frequency. • (2) (4.2) Note: The bandwidth of narrow band antenna is usually expressed as a percentage using equation (4.1), whereas wideband antenna are quoted as a ratio using equation (4.2). 4 Broadband Antenna Broadband Antenna • The definition of a broadband antenna is somewhat arbitrary and depends on the particular antenna. • If the impendence and pattern of an antenna do not change significantly over about an octave ( fu / fl =2) or more, it will classified as a broadband antenna". • In this chapter we will focus on – Loops antenna – Helix antenna – Yagi uda antenna – Log periodic antenna* 5 Broadband Antenna LOOP ANTENNA 6 Broadband Antenna Loops Antenna • Another simple, inexpensive, and very versatile antenna type is the loop antenna.
    [Show full text]
  • Antenna Catalog. Volume 3. Ship Antennas
    UNCLASSIFIED AD NUMBER AD323191 CLASSIFICATION CHANGES TO: unclassified FROM: confidential LIMITATION CHANGES TO: Approved for public release, distribution unlimited FROM: Distribution authorized to U.S. Gov't. agencies and their contractors; Administrative/Operational use; Oct 1960. Other requests shall be referred to Ari Force Cambridge Research Labs, Hansom AFB MA. AUTHORITY AFCRL Ltr, 13 Nov 1961.; AFCRL Ltr, 30 Oct 1974. THIS PAGE IS UNCLASSIFIED AD~ ~~~~~~O WIR1L_•_._,m,_, ANTENNA CATALOG Volume m UNCLASSIFIED SHIP ANTENN October 1960 Electronics Research Directorate AIR FORCE CAMBRIDGE RESEARCH LABORATORIES Can+rftc AT I9(6N4,4 101 by GEORGIA INSTITUTE OF TECHNOLOGY Engineering Experiment Station •o•log NOTIC 11ý4 Sadoqh amd P4is4,ej ww~aI~.. 1! d' ths, . 'to0 t,UL .. -+~~~~~-L#..-•...T... -w 0 I tdin #" "•: ..."- C UNCLASSIFIED AFCRC-TR-60-134(111) ANTENNA CATALOG Volume III SHIP ANTENNAS (Title UOwlnIied) October 1960 Appeoved: Mmurice W. Long, Electronics Division Submitteds A oed: Technical Information Section k Jeme,. L d, Directot Esis..ielng Expe•immnt Station Prepared by GEORGIA INSTITUTE OF TECHNOLOGY Engineering Experiment Station DOWNGRADED A-r 3 YEAR INTERVAIS. DECL~IFED AFTER 12 YEA&RS. DOD DIR 5200.10 UNC-LASSIFIED. , ~K-11. 574-1 ." TABLE OF CONTENTS Page INTRODUCTION . 1 EQUIPMENT FUNCTION ................ .................. ... 3 ANTENNA TYPE . 7 ANTENNA DATA AB Antennas ......... ................. .............. ...................... ... 15 AN Antennas ............................ ......................................
    [Show full text]
  • Wire Antennas for Ham Radio
    Wire Antennas for Ham Radio Iulian Rosu YO3DAC / VA3IUL http://www.qsl.net/va3iul 01 - Tee Antenna 02 - Half-Lamda Tee Antenna 03 - Twin-Led Marconi Antenna 04 - Swallow-Tail Antenna 05 - Random Length Radiator Wire Antenna 06 - Windom Antenna 07 - Windom Antenna - Feed with coax cable 08 - Quarter Wavelength Vertical Antenna 09 - Folded Marconi Tee Antenna 10 - Zeppelin Antenna 11 - EWE Antenna 12 - Dipole Antenna - Balun 13 - Multiband Dipole Antenna 14 - Inverted-Vee Antenna 15 - Sloping Dipole Antenna 16 - Vertical Dipole 17 - Delta Fed Dipole Antenna 18 - Bow-Tie Dipole Antenna 19 - Bow-Tie Folded Dipole Antenna for RX 20 - Multiband Tuned Doublet Antenna 21 - G5RV Antenna 22 - Wideband Dipole Antenna 23 - Wideband Dipole for Receiving 24 - Tilted Folded Dipole Antenna 25 - Right Angle Marconi Antenna 26 - Linearly Loaded Tee Antenna 27 - Reduced Size Dipole Antenna 28 - Doublet Dipole Antenna 29 - Delta Loop Antenna 30 - Half Delta Loop Antenna 31 - Collinear Franklin Antenna 32 - Four Element Broadside Antenna 33 - The Lazy-H Array Antenna 34 - Sterba Curtain Array Antenna 35 - T-L DX Antenna 36 - 1.9 MHz Full-wave Loop Antenna 37 - Multi-Band Portable Antenna 38 - Off-center-fed Full-wave Doublet Antenna 39 - Terminated Sloper Antenna 40 - Double Extended Zepp Antenna 41 - TCFTFD Dipole Antenna 42 - Vee-Sloper Antenna 43 - Rhombic Inverted-Vee Antenna 44 - Counterpoise Longwire 45 - Bisquare Loop Antenna 46 - Piggyback Antenna for 10m 47 - Vertical Sleeve Antenna for 10m 48 - Double Windom Antenna 49 - Double Windom for 9 Bands
    [Show full text]
  • Lecture 28 Different Types of Antennas–Heuristics
    Lecture 28 Different Types of Antennas{Heuristics 28.1 Types of Antennas There are different types of antennas for different applications [128]. We will discuss their functions heuristically in the following discussions. 28.1.1 Resonance Tunneling in Antenna A simple antenna like a short dipole behaves like a Hertzian dipole with an effective length. A short dipole has an input impedance resembling that of a capacitor. Hence, it is difficult to drive current into the antenna unless other elements are added. Hertz used two metallic spheres to increase the current flow. When a large current flows on the stem of the Hertzian dipole, the stem starts to act like inductor. Thus, the end cap capacitances and the stem inductance together can act like a resonator enhancing the current flow on the antenna. Some antennas are deliberately built to resonate with its structure to enhance its radiation. A half-wave dipole is such an antenna as shown in Figure 28.1 [124]. One can think that these antennas are using resonance tunneling to enhance their radiation efficiencies. A half-wave dipole can also be thought of as a flared open transmission line in order to make it radiate. It can be gradually morphed from a quarter-wavelength transmission line as shown in Figure 28.1. A transmission is a poor radiator, because the electromagnetic energy is trapped between two pieces of metal. But a flared transmission line can radiate its field to free space. The dipole antenna, though a simple device, has been extensively studied by King [129]. He has reputed to have produced over 100 PhD students studying the dipole antenna.
    [Show full text]
  • An Overview of the Underestimated Magnetic Loop HF Antenna
    An Overview of the Underestimated Magnetic Loop HF Antenna It seems one of the best kept secrets in the amateur radio community is how well a small diminutive magnetic loop antenna can really perform in practice compared with large traditional HF antennas. The objective of this article is to disseminate some practical information about successful homebrew loop construction and to enumerate the loop’s key distinguishing characteristics and unique features. A magnetic loop antenna (MLA) can very conveniently be accommodated on a table top, hidden in an attic / roof loft, an outdoor porch, patio balcony of a high-rise apartment, rooftop, or any other tight space constrained location. A small but efficacious HF antenna for restricted space sites is the highly sort after Holy Grail of many an amateur radio enthusiast. This quest and interest is particularly strong from amateurs having to face the prospect of giving up their much loved hobby as they move from suburban residential lots into smaller restricted space retirement villages and other shared residential communities that have strict rules against erecting antenna structures. In spite of these imposed restrictions amateurs do have a practical and viable alternative means to actively continue the hobby using a covert in-door or portable outdoor and sympathetically placed low visual profile small magnetic loop. This paper discusses how such diminutive antennas can provide an entirely workable compromise that enable keen amateurs to keep operating their HF station without any need for their previous tall towers and favourite beam antennas or unwieldy G5RV or long wire. The practical difference in station signal strength at worst will be only an S-point or so if good MLA design and construction is adopted.
    [Show full text]
  • Taoglas Catalog
    Product Catalog 2 Taoglas Products & Services Catalog Wireless communications are positively Our new line of LPWA antennas plays a major role changing the world, and we’re here to in realizing the value of low connectivity cost and help. Our product lineup brings the latest reduced power consumption. innovations in IoT and Transportation antenna solutions. Our Sure GNSS high precision series includes the AQHA.50 and AQHA.11 antennas to support At Taoglas we work hard to develop the next the growing demand for high precision GNSS wave of cutting-edge antenna solutions to add solutions. Our product offering comprises of both to our already market-leading product offering. embedded and external antennas for timing, Inside this catalog, you will find our ever-growing location and RTK applications. product range presented by frequency bands, giving you what you need at your fingertips to Our Antenna Builder and Cable Builder, available build your solution with complete confidence. online makes it easy for our customers to build and customize antenna and cabling solution with Taoglas continues to make significant the promise of product delivery within as little as investments in our production and infrastructure. two days. Our IATF-16949 certification approval is the global standard for quality assurance for the Our range of services continues to support automotive industry. some of the world’s leading IoT brands, helping them to optimize their products to ensure Staying on the cutting-edge of innovation, reliable performance on a global scale with we have developed new Beam Steering IoT endless design solutions including LDS. Utilizing antenna solutions.
    [Show full text]